Organic light emitting diode (OLED) is a kind of organic thin film electroluminescent device, and OLED has the advantages such as simple manufacturing process, fast response, high brightness, wide visual angle, active luminescence, ability of achieving flexible display and so on, therefore having broad application prospects.
An OLED display panel is different from a traditional liquid crystal display (LCD) panel, when the OLED display panel works, a voltage is applied across the anode and the cathode of the OLED device in the pixel unit of the OLED display panel to render the light emitting layer of the OLED device to emit light, different pixel units can emit light in different colors, and therefore full color display effect can be obtained. When an OLED device works, the voltage difference between the anode and the cathode of the OLED device should be maintained at a theoretical voltage difference, however, when the OLED device is in operation, a voltage drop can be generated as to the voltage of a power supply source due to the factors, such as process conditions, external environment, service time and so on, so there is a difference between actual voltage difference applied across the two terminals of the OLED device and the theoretical voltage difference intended to be applied across the two terminals of the OLED device, affecting the display effect of the OLED display panel.